There have been survivability requirements in NFPA 72, National Fire Alarm and Signaling Code, since the 1999 edition. The primary purpose is to enable certain circuits to maintain their ability to operate for an extended time during a fire emergency. This article provides an update on the listing certification for two-hour fire-rated cables used to meet survivability requirements. More background on survivability can be found in Wayne Moore’s Fire Focus article, “My System is Survivable (I Think),” in the April 2015 ELECTRICAL CONTRACTOR. He explained survivability and the issues now facing the industry with regard to two-hour fire-rated cables and the loss of their certification.
An installer can choose other options than circuit integrity (CI) cable and still meet NFPA 72 survivability requirements, but these other choices my not be practical. Each situation is unique. To quote Moore’s article: “The basis for the circuit survivability requirements [that began in NFPA 72 1999 through NFPA 72 2013] depended on the availability of two-hour fire-rated cable, called Type CI, that met the requirements of UL 2196. Cables successfully meeting this requirement survive in a fire test of approximately 1,800°F for two hours and remain operational.”
On Sept. 12, 2012, Underwriters Laboratories Inc. (UL) issued the following statement:
“UL has recently conducted research on a wide array of current products and systems originally certified under UL 2196, Tests for Fire Resistive Cables and ULC-S139, Standard Method of Fire Test for Evaluation of Integrity of Electrical Cables, and determined that they no longer consistently achieve a two-hour fire-resistive rating when subjected to the standard Fire Endurance Test of UL2196 or ULC-S139. Consequently, UL and ULC will not be able to offer certification to the current program related to these standards.
“As a result, manufacturers are no longer authorized to place the UL mark or ULC mark on the following products including Circuit Integrity Cable installed in ‘free air’ or ‘in conduit’:
• “UL Classified Fire Resistive Cable (FHJR)
• “UL Listed cable with ‘-CI’ suffix (Circuit Integrity)
• “ULC Listed Fire Resistant Cable-Circuit Integrity Rating (CIR) Cable (FHJRC)”
There are two issues here. First, a concern was brought to UL’s attention that, when fire-resistive cables were installed in conduit with a zinc coating, the circuit integrity was compromised by a reaction of the zinc with the copper conductors, lowering the melting temperature of the conductor. Second, during its research into this potential problem, UL found that cables and cable systems were not consistently achieving the two-hour fire-resistance rating. Since the de-certification in September 2012, UL re-established an interim certification program in December 2012 and formed a joint task group composed of both U.S. (UL 2196) and Canadian (ULC-S139) standards technical panels to study the problem in March 2013. As of March 2015, no results from these efforts have been publicly released.
So where can you find out more about the problem and solutions? There is quite a bit of information on the UL website regarding the decertification and what UL is doing about it. Go to ul.com/code-authorities/fire-code/fire-resistive-and-circuit-integrity-cables for this information.
Ed Walton, a consultant to the wire and cable industry, said: “The UL FHIT number system for each manufacturer’s product type describes the tested installation of cable, components and assembly, which leads to its certification as a two-hour fire-rated system. The cable’s electrical ‘listing’ is not affected by this qualification, and the UL disclaimer on each FHIT certification states the end-user should contact the technical service staff provided by the product manufacturer to resolve field issues.”
In addition to the updates about the interim certifications, there are FAQs on the website that help explain the issue from the UL point of view. If you click on the link to the “UL Fire-Resistive cable,” and then the “View Listings” link on the page that opens, you will see that five companies have met the interim certification requirements at various levels. At first glance, it would seem that things have returned to normal. Unfortunately, that is not the case.
If you look carefully at each certification, you will see that these are all cable systems that must be installed in conduit. There are currently no listings for stand-alone cables. As I understand this, it is because UL wants to harmonize the new U.S. standard with the Canadian one, and the Canadians currently require all of these cables to be installed in conduit.
In addition, each listing requires you to use the exact listed conduit and listed couplings indicated in the manufacturer’s UL FHIT certification. No substitutes are permitted. This contradicts the National Electrical Manufacturers Association (NEMA) publication stating that EMT and IMC conduits from NEMA manufacturers do not contain zinc.
You also must look at the installation requirements carefully. Cables can be certified for horizontal, horizontal splice, vertical and pull-box applications. Not all cables in the directory are certified for all installations or length of fire ratings. You will need to contact your cable manufacturer for installation instructions covering your type of CI cable and your installation.
In the past, cables submitted for testing were placed in an oven of approximately 1,800°F for two hours and followed immediately with a water-hose stream. The circuit was then reactivated and required to still be operational. Now, under the interim certification, UL is requiring the test to be conducted on five times the number of cables, a procedure usually reserved for in-house production tests of extrusion runs. All five tests must be passed without failure. This means that, if a manufacturer wants to get cables with various sizes of conductors listed, they will need to submit five samples of each cable for the test and for each application the manufacturer wished to be listed for (horizontal, horizontal splice, vertical, pull-box). It is interesting that the number of tests have increased. UL acknowledges the cable has never failed in the field.
What about the buildings where you have previously installed CI cable? Or what about any CI cable you have purchased but not yet installed? Certified cables manufactured prior to the decertification are still listed. As a contractor, you installed the listed cables correctly per code and the qualification certifications. But what happens now if there is a fire? Is there a liability issue?
According to the UL website, the recommendation for buildings/structures with installed systems or systems awaiting sign-off is the following: “Because of the variability in the design and construction of buildings and other structures that may have an Electrical Circuit Integrity System (ECIS), it is difficult to determine if any corrective action is needed. We recommend that code authorities, contractors, architects and building owners work with fire protection specialists and the applicable cable manufacturer to determine the reliance on these products and systems for code compliance and then decide if any action is required.”
In many cases, the manufacturer can offer an “engineering judgement” on the fire rating use of their cable in a specific application based on their extensive fire-testing experience. They go on to state that, if corrective action is required, a performance approach should be considered, and a list of possible relevant factors to consider is provided.
Moore discussed the performance approaches and what is allowed as alternatives to CI cable in his April article.
What other solutions are available? One manufacturer said it could go to another listing organization, but I was told that none of the other nationally recognized testing laboratories currently have a program in place.
The bottom line, at least for the present, is that there is not an easy solution when survivability is required. Each case must be considered on its own merit. Designers, contractors and authorities having jurisdiction will need to do their homework and work together to determine how best to protect structures and their occupants.